Catalyst for the preparation of carbonyl containing compositions

ABSTRACT

CARBONYL-CONTAINING COMPOSITIONS, SUCH AS ALDEHYDES AND KETONES, ARE SELECTIVELY AND CONVENIENTLY PREPARED IN HIGH YIELDS AND AT HIGH EFFICIENCES BY A CATALYTIC VAPOR PHASE PROCESS WHICH COMPRISES CONTACTING UNSATURATED COMPOUNDS WITH OXYGEN IN THE PRESENCE OF A NOVEL CATALYST CONTAINING A VANADIUM OXIDE DOPED WITH AT LEAST ONE, AND PREFERENTIALLY TWO OR MORE, TRANSITION METALS OR TRANSITION METAL-CONTAINING COMPOUNDS, ONE OF WHICH IS, OR CONTAINS, PALLADIUM. THE CATALYSTS EMPLOYED ARE HIGHLY ACTIVE AND SELECTIVE AT MODERATE TEMPERATURES AND PRESSURES AND HAVE INDUSTRIALLY USEFUL LIFETIME.

United States Patent Ofli e' Patented Aug. 20, 1974 3,830,757 CATALYSTFOR THE PREPARATION OF CARBONYL CONTAINING COMPOSITIONS Anthony B.Evnin, Chappaqua, Jule A. Rabo, Armonk, and Louis F. Elek, and Alan P.Risch, Peekskill, and Spiro I. Kavarnos, Ossining, N.Y., assignors toUnion Carbide Corporation, New York, N.

No Drawing. Continuation-in-part of application Ser. No. 59,338, July28, 1970, which is a continuation-in-part of application Ser. No.853,974, Aug. 28, 1969, both now abandoned. This application Feb. 24,1971, Ser.

Int. Cl. 1301i 11/08 U.S. Cl. 252-464 25 Claims ABSTRACT OF THEDISCLOSURE This application is a continuation-in-part of U.S.application Ser. No. 59,338, entitled Process for the Preparation ofCarbonyl-Containing Compositions, and Novel Catalysts Therefor, filedJuly 28, 1970 now abandoned. Ser. No. 59,338 is in turn acontinuation-in-part of Ser. No. 853,974, filed Aug. 28, 1969, nowabandoned.

This invention relates, in general, to a process for the preparation ofcarbonyl-containing compositions. In one aspect this invention isdirected to the selective preparation of acetaldehyde from ethylene inrelatively high yields and at high efiiciencies. In a further aspectthis invention relates to a novel catalyst useful for efl ecting theaforementioned process. In another aspect, this invention is directed toa process for the preparation of the catalyst.

It is well known in the literature that the reaction of certain noblemetal salts with olefins, oxygen and water in homogeneous or slurriedsystems afliords carbonyl and carboxylic compounds. For example, seeGerman Pats. 1,049,845; 1,061,767; 1,123,312; and U.S. Pats. 3,057,915;3,076,032; and 3,080,425. Particularly prominent in the literature arecases in which palladium salts are utilized in conjunction with anothermetal salt such as a cupric salt which is an effective component of aredox system. Numerous variations of these systems have also beendisclosed in the literature and utilized in the preparation of carbonylor carboxylic compounds.

However, the homogeneous systems described above suffer from severaldisadvantages. In particular, these systems typically require thepresence of strong acids, such as HCl, which necessitates utilization ofspecial and costly corrosion-resistant equipment. In addition catalystlifetimes are generally a problem due to precipitation or reduction andplating out of the expensive noble metal; thus recovery andreconstitution of the catalyst is generally difficult and costly.Finally, product purification constitutes a complication in continuouscflow operation for all but acetaldehyde, the most volatile product, andin that case removal of chlorinated by-products is troublesome.

Many of the problems that plague direct oxidations of olefins tocarbonylic compounds in the liquid phase would not be present wereoperations to be carried out in the gas phase with a heterogeneouscontact catalyst. In particular, corrosion problems and the expensiverecovery of noble metal from the product should be eliminated.

There are, in fact, a number of catalyst systems reported in theliterature which are purported to be satisfactory solid contact agentsfor direct vapor phase conversion of olefins to carbonylic compounds.Although some of these systems do solve one or more of the problemspresent in the homogeneous systems, none appears to combine all thenecessary properties of activity at moderate temperatures and pressures,high selectivity, facility of operation in inexpensive conventionalequipment and industrially useful lifetimes (see the commentary inEthylene and Its Derivatives, ed. S. A. Miller, Ernest Benn Ltd, London,1969, p. 650). In particular, systems which utilize a catalyst of thetype common in the homogeneous phase, for example, palladium salts andcopper salts wherein the catalyst is merely deposited on a support, showactivity in some cases but are not stable for industrially usefulperiods; the activity and/or selectivity of these catalysts declinewithin a day or even a few hours under virually all conditions ofoperation. Moreover, thse catalysts require continuous or frequentregeneration with highly corrosive hydrochloric acid. A likely cause ofthe rapid decline in the effectiveness of these catalysts is the absenceof an eflicient mechanism for the reoxidation of the noble metal.

Somewhat more successful are systems using noble metals and molybdenumtrioxide or .heteropolymolybdates (see, for example, U.S. Pat.3,379,651), or phosphate-molybdate combinations without the noble metal(see British Pat. 990,639). The former system, however, appear to lackindustrially useful stability since the necessity of frequentregeneration was implied. Furthermore, in olefins containing allylichydrogens the preferred point of attack with these catalysts is at theallylic position and not at the double bond since propylene affordsacrolein rather than acetone. The relatively high temperature of 220 C.was employed for this reaction. The latter system where no noble metalis employed requires temperatures of 230-350 C. to achieve modestconversions for ethylene or propylene, and the large volumes of steamutilized would complicate product separation in industrial operation.

Catalysts containing a combination of palladium and either vanadiumpentoxide or molybdenum trioxide have been employd for the directconversion of ethylene to acetic acid as set forth in U.S. Pat.3,240,805. However, it is emphasized and stated in the examples thatunder the conditions utilized no acetaldehyde was detected among theproducts. Similarly, French Pat. 1,568,- 742 is also directed to aprocess for the preparation of acetic acid from ethylene. In the severalexamples cited, the formation of acetaldehyde was mentioned only once,and then only as a minor by-product.

It is therefore an object of this invention to provide a vapor phaseprocess for the preparation of carbonyl-containing compositions whereinmany of the disadvantages heretofore known have been eliminated orminimized. Another object of this invention is to provide a processwhereby the aforementioned compounds are prepared selectively and inhigh yields. A further object of the invention is to provide a vaporphase process for the selective preparation of acetaldehyde fromethylene in high yields and high efficiencies. A still further object ofthis invention is to provide a vapor phase process for the selectivepreparation of acetone from propylene. Another object of this inventionis to provide a novel catalyst containing a vanadium oxide and at leastone, and preferentially two or more transition metals or transitionmetalcontaining compounds, one of which is, or contains, palladium. Afurther object of this invention is to provide a novel catalystcontaining a vanadium oxide, palladium or a palladium-containingcompound, and titanium or a titanium-containing compound. A stillfurther object is to provide a catalyst which has an industrially usefullifetime without replacement or reconstitution and without the necessityfor frequent regeneration (operation for a period of at least one weekis possible between in situ reactivations) These and other objects willreadily become apparent to those skilled in the art in the light of theteachings herein set forth.

In its broad aspect, the present invention is directed to a catalyticvapor phase process for the preparation of carbonyl-containingcompositions selected from the group consisting of aldehydes andketones.

The process comprises contacting, usually at a temperature not in excessof about 200 C., and substantially in the vapor phase and in thepresence of oxygen and water, an unsaturated hydrocarbon with a solidcatalyst. The catalyst contains, as its critical catalytic component, avanadium oxide doped with minor portions of at least one of thefollowing constituents:

(a) palladium or palladium-containing compounds,

(b) palladium or palladium-containing compounds and titanium ortitanium-containing compounds, and

(c) palladium or palladium-containing compounds and metal ormetal-containing compounds wherein said metal is selected from the groupconsisting of platinum, ruthenium, iridium, or osmium and thereafterrecovering said carbonyl-containing compositions.

The invention also encompasses a novel catalyst employed in this processas well as a method for its preparation.

As employed in the specification and appended claims the term transitionelements means those elements which have partly filled d and f shells inany of their commonly occurring oxidation states (Cotton and Wilkinson,Advanced Inorganic Chemistry, 2nd Ed., p. 625, 1967). By the term noblemetals is meant those metals defined as the platinum metals on page 980of the cited text reference. These metals are rhodium, ruthenium,palladium, osmium, iridium and platinum.

By the term doping (or doped) as employed throughout the specificationis meant a treatment which results in an intimate chemical interactionbetween the vanadium component and one or more of the other activecomponents used in the preparation of the catalyst. These other activecomponents are usually, but not always, present in a minor amountrelative to the vanadium component. The preferred treatment is to heatthe combination of components.

As herein before indicated the process of this invention provides aselective method for the preparation of aldehydes and ketones employinga novel catalyst which is highly selective at low temperatures andpressures and has an industrially useful lifetime. No specializedequipment is needed since severely corrosive conditions are not presentin the reaction chamber. The process operates in the vapor phase andseparation of the products is uncomplicated. The catalyst can beemployed for weeks or even months without significant changes inconversion or selectivity and after such a period the activity can befully restored by a brief heat treatment with an oxygen-containing gas.

An outstanding and major feature of this invention is the combination ofhigh activity, selectivity and stability in a single system. Operatingat conversion as high as 60%, efiiciencies of about 90% to usefulproducts can be obtained. Efiiciencies to a single product, e.g.,ethylene to acetaldehyde, of 80-85% can be obtained. Another uniquefeature of this invention is the ability to operate at low temperatures.Many of the prior art processes require temperatures in excess of 200 C.

In contrast, the process of this invention can be effected attemperatures of from about 60 to about 200 0, (still higher temperaturesmay be utilized if contact times are short), and for the preparation ofacetaldehyde more preferably from about to about C. at 1 atmosphere.Moreover, pressure is not critical; the process can be conducted at anypressures required by practical consideration, such as from 1 to 50atmospheres, or higher.

The unexpected and outstanding advantages obtained by the process ofthis invention reside, in part, in (1) the unique combination oftransition metal compounds employed in the catalyst composition and (2)the method of preparation of the catalyst.

It has been demonstrated that the vanadium component of the catalystwith or without an inert support is by itself inactive for directoxidation of ethylene even at 200 C. Above this temperature only lowactivity and little or no selectivity has been observed. With propyleneand butene, some activity is observed below 200 C. but substantiallyless than for the palladium-containing catalysts of this invention.Moreover, the use of noble metal compounds in the absence of a vanadiumoxide gives low activity and drastically reduces the stability of thecatalyst for the production of carbonyl-containing compositions. Hence,such catalysts are not suitable for industrial applications.

Thus, there are two components which have been found to be critical tothe catalyst employed in the instant process. The first component of thecatalyst must be a vanadium oxide, such as vanadium pentoxide; it ispreferred that the vanadium oxide is doped with titanium. The secondcomponent of the catalyst is or contains palladium. In addition, to thepalladium and vanadium components, the catalyst may also contain asecond noble metal component which is or contains platinum, ruthenium,iridium or osmium.

As previously indicated the vanadium oxide is a critical component ofthe catalytically active species. In most cases, the catalyst should becomprised of from about 1 to 99.5 weight percent of the vanadium oxide.However,

part of the vanadium can be replaced by another transition metal of goodredox properties such as tungsten, molybdenum, niobium, tantalum, andthe like, which metals themselves alone or in combination with palladiumshow no or only insignificant activity. For example, when part of. thevanadium was replaced with tungsten such that vanadium and tungsten werepresent in an atomic ratio of 1 to 4, the catalyst showed good activity,whereas when tungsten replaced all the vanadium the catalyst was totallyinactive. Atomic ratios of vanadium to tungsten of up to 1 to 12. canalso be employed. The palladium or palladium-containing component can bepresent in the range of from about 0.001 to 20 weight percent, based onthe total weight of catalyst and calculated as the noble metal. Thecatalyst can be unsupported but preferentially it is supported. In thecase of a supported catalyst system the preferred catalysts are thosewherein the vanadium oxide is present within the range of from about 1to about 30 weight percent, and still more preferably from about 3 toabout 20 weight percent, and the palladium component from about 0.01 toabout 3 Weight percent, and still more preferably from about 0.01 toabout 1.0 weight percent, all calculated as the metal based on the totalweight of the catalyst.

It has been found that the presence of titanium significantly improvesthe performance and, in particular, the activity of the vanadiumoxide-palladium catalyst. Its application permits reduction of thepalladium content while maintaining high catalyst productivity. Thepresence of titanium also permits operation at lower temperatureswithout loss of productivity; better efficiencies are obtained at thelower temperature. The titanium can be applied in amounts as little as0.01% by weight or as much as 40% by weight of the vanadium oxide;advantages are realized throughout the range. The titanium-vanadiumcombination in the absence of palladium oxidized little or no ethyleneunder the typical reaction conditions.

The presence of another noble metal, in addition to the vanadium andpalladium components, was also found to impart increased activity. Forinstance, in the case of ethylene the addition of as little as 0.1percent ruthenium which was approximately 10 weight percent based on theweight of palladium, produced a marked increase in activity. In contrasta catalyst containing only Ru and V (i.e., no palladium present) wasinactive under the same reaction conditions. However, when the threecomponents were employed together, an unexpected and large increase inactivity was obtained. This synergistic effect which is only observedwhen one of several specific noble metal couples are employed permitsoperation at lower temperatures at which conditions better efiicienciesmay be achieved.

In addition to ruthenium, the metals, platinum, iridium and osmiumprovide a synergistic increase in activity similar to ruthenium whenemployed as a third component of the. catalyst. When a third componentis employed it can be present in the catalyst within a similarconcentration range as that of palladium, i.e., from about 0.001 toabout 3 weight percent, and preferably from about 0.01 to about 1.0weight percent, calculated as the metal.

The composition of the catalyst is not restricted to one containingvanadium oxide and palladium, vanadium oxide-titanium and palladium, orvanadium oxide-palladium and the second noble metal component asdescribed above. It has been found that the performance of the catalystof this invention can be significantly improved if the noble metalcomponent is applied in the form of a compound containing the noblemetal, an additional transition metal such as vanadium, chromium andtitanium, and oxygen. Consequently, upon application of these noblemetal components the additional transition metal is also incorporated inthe catalyst.

The catalysts of this invention can be employed without a support, inwhich case small amounts of binder such as silica, clay, and the likemay be added to improve structural strength. The catalyst can also becontained on an inert low surface area carrier (typically less thanmeters gram) such as alpha-aluminum oxide, silicon carbide, zirconiumdioxide, zinc oxide, porous glass, and the like. Whether a support isemployed or not, will largely be dependent upon the particular equipmentutilized in the preparation of the carbonyl-containing composition.

To obtain a catalyst with superior performance it is desirable that thepreparation of the catalyst is carried out in such a way that thevanadium oxide component is present in a small particle size,preferentially of less than one micron. Excellent catalysts are preparedby the spray deposition of a solution or solutions containing the majorcatalytic components onto alpha-aluminum oxide with a concurrent andrapid removal of the solvent (spray-dry technique).

The temperature applied in the spray-dry technique may be chosen in sucha way as to afford not only the removal of the solvent but also toinduce the formation of the vanadium oxide phase and the formation of avanadium oxide-noble metal interface which is important for the uniquestability, required for industrial application.

Another technique for the preparation of the catalyst involvesapplication of the palladium to a preformed vanadium oxide phase throughion exchange either with the hydrogen or hydroxyls of the vanadium oxidesurface. The ion exchanged system is then heated with anoxygen-containing gas to afford the active catalyst.

The doping of the vanadium oxide by titanium, titanium-containingcompounds, by the palladium compounds or by the additional noble metalcan also be carried out in an independent step. In this step thecatalyst preferentially containing all substantial components is heattreated, generally in an oxygen-containing gas such as ambient air.Since a strong interaction between the vanadium oxide and other metalcomponents is important for catalyst stability and industrially usefullifetimes, chemical additives or noble metal-transition metal compoundsmay be applied in catalyst preparation in addition to the heat treatmentin order to facilitate the interaction.

In the activation of the catalyst it has been observed that temperaturesof from about 200 C. to about 500 C. and heating periods in excess of 3hours are satisfactory, such as at least 5 hours. In practice, thedoping is essentially completed after heating for about 16 hours 7 at400 C. Lower temperatures, of course, require the longer heatingperiods.

As indicated above the doping step Whether performed concurrently withspray-drying or as a separate step, is essential to provide a catalystwhich is selective, active and stable for the oxidation of olefins.Moreover, the combination of thermal activation with a spray depositionof the active component provides uniformity, prevents the growth oflarge crystallites, eliminates peeling or leaching of the catalyst, andgenerally affords a stable, active and selective catalyst.

In practice, it has been found that a wide variety of vanadium and noblemet-a1 compounds, including the noble metals themselves, can be employedin the preparation of the catalyst of this invention. For the firstcomponent of the catalyst, i.e., the vanadium oxide, illustrativestarting materials include, among others ammonium vanadate, vanadylhalides, such as vanadyl chloride, organic vanadium compounds such asvanadyl acetonlyaceton-ate, and the like. The only requirement of thestarting material is that it can be converted to the oxide, in theactivation step of this invention. When the vanadium is to be doped withtitanium, the titanium can be introduced in a variety of forms.Illustrative titanium compounds which can be employed include, amongothers, inorganic compounds such as, the titanium halides, for example,titanium trichloride, titanium tetrachloride, titanium tetrabromide,titanium tetraiodide, and the like, titanium sulfate, titanium nitrate;the organic titanium compounds, such as titanium oxalate, titaniumacetonylacetonate, the alkyl titanates sudh as the butyl titanates, andthe like. The titanium can be introduced with the vanadium salt or afterformation of the vanadium pentoxide matrix. An additional activationstep, i.e., oxygen-containing gas at elevated temperatures, is requiredin the latter case.

As previously indicated, at least one of the noble metal components ofthe catalyst must be palladium or a palladium-containing compound. Ifadditional noble metals or noble metal-containing compounds areemployed, they are chosen from those which are or contain platinum,ruthenium, iridium, or osmium. Illustrative compounds which can beemployed in addition to the noble metals themselves include the halides,e.g., palladium chloride, ruthenium chlonide, osmium chloride, platinumchloride, iridium chloride, palladium nitrate, organic noble metalcompounds, such as the acetates and acetonyl 'acetonates, e.g.,palladium acetate, ruthenium acetate, palladium acetonyl acetonate, andthe like or the noble metals themselves.

A preferred class of palladium compounds which can be applied withadvantage as a source of palladium are palladium-transition metaloxides; in most cases salts in which palladium usually plays the role ofthe cation and the transition metal is part of the anion. The palladiumsalts mentioned above are usually formed either from M -O acids or fromtheir ammonium salts by cation exchange with palladium. (M representstransition metals; 0 represents oxygen; and x and y whole numbers).Examples of this class of compounds are the palladium salts ofvanadates, chromates, titanates, manganates, and the like. Thesecompounds upon application by themselves on alpha-alumina supportusually show only little activity; however, upon application onsupported vanadium pentoxide and upon doping by heat treatment they giverise to catalysts of excellent catalystic properties (selectivity,activity, Pd-utilization). As mentioned above, the titanium system, inparticular, shows enhanced activity. The preferred method for theapplication of these compounds is through their solutions, but highsolubility of these compounds is not a requirement. In certain casesthese palladium compounds may be prepared and applied at the same timein the presence of the supported vanadium oxide.

As hereinbefore indicated the process of thls invention can be utilizedfor the preparation of carbonyl-containing compounds from a wide rangeof unsaturated hydrocarbons. The process is particularly attractive forconversion of lower alkenes to aldehydes and ketones. For example,ethylene can be converted to acetaldehyde, propylene to acetone,n-butenes to methyl ethyl ketone and the like. Illustrative otherunsaturated compounds which can be employed include, among others,higiher alkenes, cycloalkenes, dienes and 'aralkyl compounds such astoluene.

In contrast to many of the processes presently in use, the conversion ofthe olefinic compounds is conducted in ths vapor phase and at moderatetemperatures. A wide variety of known vapor phase techniques andengineering designs can be employed. For example, the catalyst can beutilized in any of several fixed, moving or fluidized bed systemsthrough which the unsaturated compound and oxygen pass and from whichthe reaction products are Withdrawn and separated.

Another important feature of the process of this invention is theflexibility in feed composition. The oxygen, unsaturated compound andwater can be varied over wide ranges dictated so as to circumvent theexplosion limits. Saturated alkanes such as methane or ethane may beused as diluents. Minor concentrations of acetylene or allene; which aredeleterious in the solution oxidation of ethylene with PdCl -CuC1 can betolerated by the catalyst of this invention.

The following examples are illustrative:

EXAMPLE I 'A concentrated hydrochloric acid solution (3 liters)containing 489 grams of NH VO and 32 grams of PdCl was spray drydeposited on 1806 grams of alpha-A1 After loading, the catalyst wasactivated by heating at 400 C. in a stream of air for 16 hours.Elemental analysis indicated that the catalyst contained 0.8% Pd and Vby weight.

A 100 gram sample of the catalyst was placed in a vertical Pyrex tube. Apremixed gas stream consisting of ethylene, air and water vapor, in arespective mole ratio of 1:20:9 was introduced to the catalyst at 1atmosphere at the rate of 23 liters/hour with a contact time of 11seconds; this set of conditions are henceforth referred to as thestandard conditions. The temperature of the catalyst bed was maintainedat 140 C. The eflluent was analyzed both by gas chromatography, byisolation and spectral techniques. The conversion of ethylene was 75%and the efiiciency to acetaldehyde was 69%. Minor products were aceticacid and CO At 115 C. the conversion of ethylene was 19%.

A catalyst prepared as described above and operated continuously at 140C. for over I160 [hours showed no change in activity or selectivity.

EXAMPLE II A 40 gram sample of the catalyst described in Example I wasplaced in a glass-lined, steel, tubular reactor maintained at 115 poundsper square inch absolute (p.s.i. abs.) pressure and at a temperature of146 C. A feed consisting of C H 0 N and water vapor in the ratio 1:3.5:26.5 :3.2 was introduced to the catalyst at the rate of 65 liters/hour(STP). The conversion of ethylene was 36% (38 mmole/hour) and theefiiciency to acetaldehyde was 68%. During a run of 110 hours duration,there was less than a decline of activity. (In other experiments, it wasfound that substantially higher space time yields of acetaldehyde couldbe obtained by judicious choice of temperature, pressure, and gasvelocity.)

In another experiment with a catalyst prepared as in Example I andutilized under conditions similar to those above for an extended period,a decline in activity similar to that above was observed. The catalystwas restored to its original level to activity by treatment with air for1.5 hours at 400 C.

EXAMPLE III A catalyst was prepared as described in Example I exceptthat the metals were introduced as Pd(OAc) and vanadylacetonylacetonate. A methanol solution of 111.4 grams of vanadylacetonylacetonate and 4.1 grams of Pd(OAc) were spray-dry deposited into180.6 grams of alpha-A1 0 and the catalyst was then activated at 400 C.for 16 hours. Activity and selectivity were virtually identical to thecatalyst prepared from the halide salts. Under the above conditions,conversion of ethylene was 76% and the efliciency to acetaldehyde 66%.

EXAMPLE IV An aqueous nitric acid solution (pH approximately 1) of CrO'and Pd('NO in a 1:1 molar ratio was added slowly to 30% aqueous ammonia.Yellow crystals formed immediately with an approximate composition of Pd(NH .CrO

A sample of V 0 supported on alpha-A1 0 was prepared by spray-drying 489grams of NI-I VO dissolved in 2,500 cubic centimeters of I-I'Cl onto1806.0 grams of support. The V 0 phase was developed by calcination at400 C. for 16 hours. A 264.2 gram sample of this material was lo'aded bythe spray-dry method with 600 ml. of an aqueous solution containing 6.4grams of the Pd-Cr compound described above. After this application thecatalyst was calcined for 48 hours at 400 C. in air.

A 40 gram sample of this catalyst was placed in a glass lined, steel,tubular reactor and maintained at 145 C. and p.s.i. abs. A feedconsisting of ethylene, nitrogen, oxygen and water vapor in the ratio of1:22:33 was introduced to the catalyst at the rate of 66 liters/hour.The conversion of ethylene was 21 mmole per hour and the efficiency toacetaldehyde was 83 EXAMPLE V A solution (containing some suspendedmaterial) of 10.8 grams of ammonium metavanad'ate, 86.8 grams of (NH W,O -6H O and 5.16 grams of PdJ(NO in 1500 milliliters of hot Water wassprayed onto 180.6 grams of alpha-alumina. The catalyst was activated inair for 16 hours at 400 C.

A 40 gram sample of the catalyst was placed in a glass lined, steel,tubular reactor under a pressure of 115 p.s.i. abs. and at 146 C. A feedconsisting of ethylene, nitrogen, oxygen and water vapor in the ratio1:24:2.7:3.5 was introduced to the catalyst at a rate of 64 liters/hour.The conversion of ethylene was 42% (42 mmole/hr.) and the efiiciency toacetaldehyde Was 61% Using the same volume of catalyst, temperature andpressure but operating in a stainless steel, recirculating, back mixedreactor similar results are obtained. With a feed consisting ofethylene, air and water in the ratio of 1:152 which was introduced atthe rate of 60 liters/hour, the conversion of ethylene was 30%; theefficiency to acetaldehyde was somewhat lower due to the back mixing ofthe product.

EXAMPLE VI A solution of 37 grams of palladium nitrate in 1 liter ofwater was added in a dropwise manner during 1 hour to a stirred solutionof 50 grams of ammonium metavanadate in 4 liters of water. A solution 1M in ammonia was simultaneously added as needed to maintain the pH closeto 6. When the additions were complete the resulting orange productcontaining 17.7% palladium and 30.7% vanadium (palladium polyvanadate)was separated by sedimentation from the hydrous palladium oxidesimultaneously formed in the reaction. The orange product was desiccatedin vacuo overnight. The resulting dried product was identified by X-raydilfraction as a palladium polyvanadate. 38 grams of this product wereobtained.

A solution of 20 grams of ammonium chloride in 500 milliliters of waterwas heated to boiling and 4 grams of palladium polyvanadate added to it.The mixture was spray dried onto 200 grams of alpha-alumina whichalready contained 17% by weight of vanadium pentoxide. A portion of thecomplete catalyst was heated for 66 hours in air at 400 C. It contained0.4% by weight of Pd.

A 40 gram sample of this catalyst was placed in a glass lined, steel,tu'bular reactor under a pressure of 115 p.s.i. abs. and at atemperature of 146 C. A feed consisting of ethylene, oxygen, nitrogen,and water vapor in the ratio of 1:2.3 516.5 :1.75 was introduced to thecatalyst at the rate of 64 liters/hour (STP). The conversion of ethylenewas 20% (25 mmole/hour) and the efliciency to acetaldehyde was 80%.After 124 hours of continuous operation, there was an approximately 10%decline in activity but the selectivity was essentially the same.

A catalyst was prepared as described above except that the palladiumpolyvanadate was introduced to the V alpha-A1 0 system by soaking ratherthan spraying and the palladium was present in the final catalyst to theextent of 0.1% by weight.

The catalyst was utilized in the reactor described above with a feed ofethylene, oxygen, nitrogen and water vapor in the ratio of 1:3:27:3.5.The conversion of ethylene was 26.5% (25 mmole/hour) and the efiiciencyto acetaldehyde was 80%.

EXAMPLE VII In order to demonstrate the necessity of activating thecatalyst prior to use, a catalyst was prepared as described in Example Iexcept that it was heated in helium instead of air at 400 C. for 16hours. This atfcrded a system that was totally inactive for theconversion of ethylene under the standard reaction conditions i.e.,those set forth in Example I. When the same catalyst was activated inair 'at 120 C. instead of 400 C. for 16 hours the system was alsototally inactive.

EXAMPLE VIII A catalyst prepared as in Example I was reduced withhydrogen for 24 hours at 400 C. Under the standard reaction conditions,the conversion of ethylene was erratic, settling at about 24% with loweffi'ciency to acetaldehyde.

EXAMPLE In order to demonstrate the stability of the catalysts of thisinvention a catalyst was prepared which did not contain vanadium. Thecatalyst was prepared by spray dry deposition of an HCl solution of 6.4grams PdCl to 361.2 grams of alpha A1 0 followed by activation at 400 C.in air for 16 hours. The catalyst contained 1.3% Pd. Under the standardoperating conditions, initial results (tfiISll hour) indicated a 49%conversion of ethylene and a low efiiciency to acetaldehyde. Within 4hours however, the activity had virtually disappeared; con-versions weredown to 6% and the efficiency to acetaldehyde was less than 10%.

Similarly, a catalyst prepared as described in US. Pat. 3,419,618 bydepositing palladium metal or -Pd(NO on alpha-A1 0 and converting toPdO, as indicated by X-ray diffraction, showed a short life (few hours)and low activity. The catalyst contained about 0.8% Pd by weight.

EXAMPLE X A catalyst was prepared as in Example I except that rutheniumchloride was substituted for the palladium chloride. Theruthenium-vanadium atomic ratio was the same as the palladium-vanadiumratio of Example I. The catalyst was inactive under standard conditions;the conversion of ethylene was less than 1%. Another catalyst wasprepared by depositing ruthenium chloride on a catalyst containing V 0on alpha A1 0 and activating at 400 C. for 16 hours. This catalyst wasalso inactive under the standard conditions employed.

EXAMPLE XI In order to demonstrate the inactivity of ruthenium alone, ahydrochloric acid solution of 8.16 grams of RuCl was spray deposited on391.8 grams of alpha- Al O and then activated at 400 C. for .16 hours.Under the standard reaction conditions the catalyst was inactive; theconversion of ethylene amounted to less than 1%.

EXAMPLE XII A solution of 369.6 grams of (NI-I Mo O -4H O and 16 gramsof PdCl in approximately 2 liters of aqueous ammonium hydroxide (pH 8)was spray deposited onto 903 grams of alpha alumina. The catalyst wasthen acticated in air at 400 C. For 16 hours.

A 40 gram sample of the catalyst was placed in a stainless steelrecirculating, back-mixed autoclave reactor. A feed consisting ofethylene, air and water vapor was introduced to the catalyst in theratio of 1:15.5:1.7 at the rate of 65 liters/hour (STP). There was noreaction at 145 C. and the temperature was gradually raised to 190 C. Atthe higher temperature the only detectable product was CO EXAMPLE XIII Asolution (some suspended material) of 217 grams of (NH4)6W7O24"6H2O and14.8 grams of Pd(NO in about 2 liters of water (pH 6) was spray driedonto 451.5 grams of alpha-alumina. The resultant catalyst was activatedin air at 400 C.

A 40 grains sample of the catalyst was placed into a stainless steel,recirculating, back-mixed autoclave reactor under p.s.i. abs. pressureand at C. A feed consisting of ethylene, air and water vapor in theratio of 1:15.5 1.7 was introduced to the catalyst at the rate of 65liters/ hour. No conversion or ethylene was evident at 145 C. and thetemperature was raised to C. Under these conditions a small conversionof ethylene 3%) was evident and CO and CH CO H were detected.

EXAMPLE XIV In order to demonstrate the effect of the presence of asecond noble metal on ethylene conversion, a catalyst Was prepared as inEaxmple I except that RuCl was added. After the PdCl and NH VO had beendeposited, a hydrochloric acid solution of RuCl was introduced. Thecatalyst was next activated at 400 C. in air for 16 hours. Elementalanalysis of the activated catalyst indicated 0.8% Pd, 0.1% Ru and 9.8%V. With the feed used in Example I but a temperature of 135 C. (contacttime 11 seconds), the conversion of ethylene was 88% and the efliciencyto acetaldehyde was 57%. At 125 C. the conversion was 47% and theefficiency to acetaldehyde was 72%. At 111 C. the conversion was 35% andthe efficiency to acetaldehyde was 90% EXAMPLE XV The catalyst wasprepared as in Example XIV except that the activated catalyst contained0.8% Pd and 0.46% Ru and 10% V. At 113% C. the conversion of ethylenewas 60%; the efficiency to acetaldehyde was 87%. A separate sample ofcatalyst was run continuously for 70 hours and showed no change inactivity or selectivity during that period.

EXAMPLE XVI The catalyst was prepared as described in Eaxmple XIV exceptthat the activated catalyst contained 0.8% Ru. At 111 C. with the samefeed as in Example I a 50% conversion of ethylene was observed andv theefiiciency to acetaldehyde was 86%. A separate sample was run for 1 weekwith no change in activity or selectivity.

1' 1 EXAMPLE XVII A catalyst was prepared by spray-dry deposition of anHCl solution of IrCl PdCl and NH VO onto alpha A1 The catalyst was thenactivated in air at 400 C. for 16 hours. The atomic ratio of Pd, Ir andV in the catalyst is 1:1:25. The catalyst was very active under standardconditions and at 115 C. with standard feeds, conversion of ethylene was70% and efliciency to acetaldehyde was 70%. No change in conversion orefliciency was observed during 48 hours.

EXAMPLE XVIII A catalyst was prepared as described in Example XVIIexcept that platinum was employed in place of ruthenium. The catalystwas activated in air at 400 C. for 16 hours. The Pd and Pt were presentin an atomic ratio of 1:1. At 120 C. using the feed conditions describedin Example I, the conversion of ethylene was 80% and the efficiency toacetaldehyde was 80%. A sample of this catalyst was run at 120 C. forover 100 hours without any diminution in activity.

EXAMPLE XIX A catalyst was prepared and activated as described inExample X. It was then loaded via the same spray technique with an HClsolution of PdCl and then reactivated in air at 400 C. The finalcatalyst contained 0.8% Pd, 0.9% Ru and 8% V by weight.

At 130 C. (contact time 11 seconds) with a standard feed an 85%conversion of ethylene was observed with 55% efiiciency to acetaldehyde.At 115 C. conversion was 60% and efficiency to acetaldehyde 83% Theactivity and selectivity of this catalyst were undiminished after 200hours of use.

EXAMPLE XX A palladium peroxytitanate compound was prepared by additionof Pd(NH Cl to a solution resulting from the addition of TICL; to excessH 0 and adjustment of the pH to 8-10 with excess ammonia. A solution of3.2 grams of the palladium peroxytitanate in a mixture of aqueousammonia (150 cc.) and 30 percent H 0 (350 cc.) was sprayed onto 253.1grams of a support containing 17 percent V O and 83 percent a-Al2O3. Thecatalyst was activated at 400 C. in air for 48 hours prior to use. Thecatalyst contains 0.4 percent palladium, 0.4 percent titanium by weight.

A 40 gram sample of the catalyst described above was placed in a glasslined stainless steel tubular reactor maintained at 115 p.s.i. abs. andat a temperature of 14-6 C. A feed consisting of C H 0 N and H 0(gaseous), in the ratio 1 :3:21 :3 was introduced to the catalyst at therate of 65 liters/hour (STP). The conversion of ethylene after one daywas 41 mmole/hr. and the efiiciency to acetaldehyde was 75 percent.Under other conditions (higher flows and temperatures) yields ofacetaldehyde of 2.5 mole/l. cat/hr. were achieved.

EXAMPLE XXI A solution of 109.3 grams NH VO 3.34 grams PdC1 and 5 cc.TiCl in that order, were dissolved in 1 liter of hot hydrochloric acid,concentrated to 800 cc. and spraydried onto 409 grams of alumina. Thefinal composition contained 0.4 percent P'd, 0.4 percent Ti and 17percent vanadium pentoxide by Weight. The sample was then activated at400 C. for 40 hours. Utilization of the catalyst under the conditionsdescribed in Example XX resulted in conversion of 44 mmole ofethylene/hour with an efiiciency to acetaldehyde of 75 percent.

A catalyst prepared in the same way but containing 0.1% Pd, 0.4% Ti and17% vanadium pentoxide was found to be much more active than a catalystwith 0.1% Pd and 17% vanadium pentoxide. Comparative experiments werecarried out in a stainless steel, back mixed autoclave reactor. Catalystsamples of 40 cc. were utilized and the conditions were: temperature,170 C.;' pressure, p.s.i. absolute. About 200 l./hr. (STP) of a mixtureof C H 0 N and H 0 (gaseous) in the ratio 1:1.6:l4:2 were fed to thecatalyst. With the Pd-Ti-V catalyst the conversion of ethylene wasmmole/hr. and the efiiciency to acetaldehyde was 68%. With the Pd-Vcatalyst the conversion Was 76 mmole/hr. and the efiiciency toacetaldehyde was 71% EXAMPLE XXII A solution of 129. 3 grams of NH VOand 6.0 cc. of TiCL, were dissolved in 1 liter of hot HCl andspray-dried onto 484.3 grams of [rt-A1 0 After activation in air at 400C. the material contained 0.4 percent titanium and 17 percent vanadiumpentoxide by weight. A solution of 0.88 grams of palladium polyvanadate(see Example VI) in 40 ml. of 4 M NH Cl was soaked onto grams of thetitanium-vanadium-alumina system described above. The system was thendried at 120 C. for 3 hours and then calcined in air for 17 hours at 400C. The final composition had approximately 0.1 percent by weightpalladium. Utilization of this catalyst under the conditions describedin Example XX resulted in conversion of 32 mmole of ethylene/hour withan efliciency to acetaldehyde of 72 percent.

EXAMPLE XXIII Using the reagents and proportions described in Example Ibut applying the active components to the support by soaking followed byslow vacuum removal of the solvent afforded a catalyst somewhat inferiorto that of Example I. The catalyst particles were more friable, crustsdeveloped on the surface of the catalyst and loss of some of the activecomponents occurred during the first few hours of operation.

Conversion of ethylene and efficiencies to acetaldehyde were generally10-15% lower than in Example I at similar conditions. Reactivation ofthis catalyst after use for an additional 63 hours at 400 C. in airresulted in an improvement in the catalyst performance.

EXAMPLE XXIV An experiment with propylene was carried out with thecatalyst described in Example I and under substantially the sameconditions as in Example I. The only ditferences were that thetemperature was 165 C. (contact time 6 sec.), and the feed consisted ofpropylene (1.4 l./hr.), air (28 l./hr.) and water vapor (10 l./hr.). Theconversion of propylene was 43%. The over-all efiiciency to acetone was76%. A separate sample of this catalyst was operated continuously forover 40 hours without change in behavior.

Under these same conditions with a catalyst prepared as in Example I butcontaining 2% Pd by weight and operating at 150 C. (contact time 9 sec.)similar results were obtained. The conversion was 45% and efliciency toacetone 70%.

EXAMPLE XXV The catalyst was prepared as in Example XVII and utilized ina Pyrex tubular reactor at C. and 1 atmosphere. The feed consisted ofl-butene, air and water vapor in the ratio 1:20:17 at the rate of 27.5liters/ hour. The conversion of lbutene under these conditions was about18%. The efficiency to methyl ethyl ketone was 55%. The major sideproducts were acetic acid, and to a lesser extent, acetaldehyde. Similarresults were obtained starting from 2-butene.

EXAMPLE XXVI A catalyst was prepared as described in German Pat.1,049,845 Example XXIII, and utilized under the conditions of Example I;this preparation does not involve doping by heat treatment. Elementalanalysis indicated that the catalyst contained 0.7% Pd, 1.7% Cu. 0.4% Feand 0.5% V; on a-alumina. Under the conditions of 13 Example I theinitial conversion of ethylene was 69% with a selectivity toacetaldehyde of 87%. Within 23 hours, however, the conversion haddeclined to 36%.

Although the invention has been illustrated by the preceding examples,it is not to be construed as being limited to the materials employedtherein, but rather, the invention encompasses the generic area ashereinbefore disclosed. Various modifications and embodiments thereofcan be made without departing from the spirit and scope thereof.

What is claimed is:

1. A process for the preparation of a catalyst useful in the oxidationof unsaturated hydrocarbons to carbonylcgntaining compositions whichprocess comprises the steps (l) forming a mixture of:

(i) a vanadium salt, and at least one component selected from the groupconsisting of:

(a) a palladium salt and a titanium salt,

and (b) a palladium salt and a metal salt wherein said metal is selectedfrom the group consisting of platinum, ruthenium, iridium or osmium, and(2) doping said component into said vanadium salt by heating at atemperature of from about 200 C. to about 500 C. for at least hours inthe presence of oxygen or an oxygen containing gas.

2. The process of claim 1 wherein said doping is effected by heating ata temperature of about 400 C. for about 16 hours.

3. The process of claim 1 wherein said catalyst is contained on acarrier.

4. The process of claim 3 wherein said carrier is alphaalumina.

5. The process of claim 1 wherein said mixture is formed by spray-drydepositing onto a carrier a solution of said vanadium salt and saidcomponent.

6. The process of claim 5 wherein said solution contains ammoniumvanadate.

7. The process of claim 5 wherein said solution contains vanadiumacetonylacetonate.

8. The process of claim 5 wherein said solution contains palladiumchloride.

9. The process of claim 5 wherein said solution contains palladiumacetonylacetonate.

10. The process of claim 5 wherein said solution contains ammoniumvanadate and palladium chloride.

11. The process of claim 5 wherein said solution contains ammoniumvanadate, palladium chloride and titanium chloride.

12. The process of claim 5 wherein said solution contains ammoniumvanadate, palladium chloride and ruthenium chloride.

13. The process of claim 5 wherein said solution contains vanadylchloride.

14 14. The process of claim 5 wherein said solution contains a palladiumsalt selected from the group consisting of palladium vanadate, palladiumchromate, palladium titanate and palladium manganate.

15. The process of claim 14 wherein said salt is palladium chromate.

16. The process of claim 14 wherein said salt is palladium titanate.

17. The process of claim 14 wherein said palladium salt is palladiumpolyvanadate.

18. A catalyst prepared by the process of claim 14. 19. A doped catalystcomprised of a vanadium oxide and minor portions of:

(a) palladium oxide and at least one of (b) titanium oxide, or (0) metaloxide wherein said metal of said oxide is selected from the groupconsisting of platinum, ruthenium, iridium or osmium.

20. The catalyst of claim 19 comprised of from about 1 to about 20weight percent vanadium oxide, from about 0.01 to about 1.0 weightpercent palladium oxide, and titanium oxide in an amount up to about 40weight percent based on the weight of vanadium.

21. The catalyst of claim 19 contained on a support.

22. The catalyst of claim 19 contained on alpha-aluminum oxide.

23. The catalyst of claim 19 wherein said vanadium oxide is present inan amount of from about 1 to about 99.5 percent by weight.

24. The catalyst of claim 19 wherein palladium oxide is present in anamount of from about 0.001 to about 20 percent by weight.

25. The catalyst of claim 19 wherein ruthenium oxide is present in anamount of from about 0.001 to about 3 percent by weight.

References Cited UNITED STATES PATENTS 3,106,579 10/1963 Hornig et al260597 B 3,207,703 9/1965 Innes et al. 252464 X 3,240,805 3/1966Naglieri 252441 X 3,523,964 8/1970 Kober et a1. 252472 X 3,563,9632/1971 Beier et al 252472 X FOREIGN PATENTS 913,449 12/ 1962 GreatBritain 252464 1,568,742 4/1969 France 252597 B DANIEL E. WYMAN, PrimaryExaminer W. J. SHINE, Assistant Examiner US. Cl. X.R.

252466 PT, 470, 472; 260597 B

